Almost all existing aggregate signature schemes are based on bilinear pairing which leads to high computational cost. In order to solve this problem under different network environment, two new certificateless aggregate signature schemes without bilinear pairing CLAS-Ⅰ and CLAS-Ⅱ are proposed in this paper. The proposed schemes are provably unforgeable in the random oracle model under the discrete logarithm assumption, and also have the security properties of public verifiability. Moreover, compared with other existing aggregate signature schemes in the computationally complexity, the proposal are more efficient. Meanwhile, the scheme CLAS-Ⅰ can be used for high bandwidth network environment because the length of signature is long, and the scheme CLAS-Ⅱ can be used in a narrow bandwidth network environment since it is the shortest certificateless aggregate signature and the number of users does not correlate to the length of the signatures generated by CLAS-Ⅱ,.